Video cameras are increasingly used to make dimensional measurements. Many of these systems use interpolation of the pixel data, with some systems claiming to find edges with precision of l/100 of a pixel. We have studied the response of single pixels of a CCD camera to a small circle of light. The illuminated area has a diameter of less than l/3 of a pixel, and the relative response of the pixel to the position of the light was measured. We have found that the active responsive area of the pixel is quite small compared to the total area of the pixel. Some implications of these results on the use of cameras as measurement devices are discussed.
Proceedings Title: International Dimensional Metrology Workshop
Pub Type: Conferences
CCD camera, pixel geometry, pixel sensitivity, systematic errors, video metrology